Do bulls really hate red colours?

The popular myth seen across the world is bulls get angry on seeing red.
But this is not true actually.Bulls are colourblind. They are dichromates. They perceive white and black colour.

Then why red cloths are seen to bulls in game to make them angry.Actually bulls attack not seeing red colour but waving of the cloth by metador. It is waving that cause them to charge not the colour of the cloth.They feel threat from moving objects.